This application is based on Patent Application No. JP2000-355964 filed in Japan, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an improved image forming apparatus and image forming method. More specifically, the present invention relates to an improved image forming apparatus and method for outputting a general-purpose sheet such as plain paper, overhead projector transparency and the like, as well as a concavo-convex sheet having a concavo-convex surface on which is formed many concavities capable of receiving toner and from which toner is removable.
2. Description of the Related Art
Currently, recording sheets such as copier paper, printer paper, OBH transparencies and the like are used in large volume for forming images (e.g., text and graphics) in copiers, printers and the like. Most of these recording sheets are disposed of after use, and present both an environmental problem and a resource problem. Accordingly, it is desirable to use a recording sheet from which an image formed on the recording sheet can be removed repeatedly in order to solve this problem.
In practice, the toner adhered to a recording sheet used in copiers, printers and the like is insoluble in water and is not easily removed. Furthermore, although removing toner by the use of organic solvents has been considered, there is concern of adverse effects on humans and the environment.
To resolve these problems, a concavo-convex sheet having a concavo-convex surface on which is formed many concavities capable of receiving toner and from which toner is removable (hereinafter referred to as xe2x80x9cconcavo-convex sheetxe2x80x9d), and an image forming apparatus using this sheet has been proposed, for example by the present applicant in Japanese Patent Filing No. H11-281812. This image forming apparatus uses the electrophotographic method, and develops an electrostatic latent image formed on an image carrier (photosensitive drum) with toner, and thereafter electrically transfers the toner to the concavo-convex sheet. At this time most of the toner adheres to the concavities of the concavo-convex sheet, but since part of the toner adheres to the convexities, and electrostatic force is applied to the toner on the convexities so as to remove the toner. Since the toner within the concavities forming the image on the concavo-convex sheet is protected from external action (e.g., rubbing by fingers and the like) by the convexities there is no need to provide a fixing device for adhering the toner to the sheet in the image forming apparatus. However, since toner within a concavity is held within the concavity only by the electrostatic force from the electrical load of the sheet in the transfer process, the toner within the concavity can be removed by the action of an electrostatic force.
The present inventors believe the consumption of recording papers can be effectively reduced by using a general-purpose sheet such as widely used plain paper and OHP transparency for long-term storage and presentations, while using a concavo-convex sheet, which can be used for repeated image formation and image removal, for temporary recording and reading.
In view of the previously described conditions, an object of the present invention is to provide an improved image forming apparatus and image forming method More specifically, an object of the present invention is to provide an improved image forming apparatus and image forming method for forming images on both a concavo-convex sheet and a general-purpose sheet which does not require special processing.
In order to attain these and other objects, an image forming apparatus according to an embodiment of the present invention comprises a first mode for forming an image by applying toner to a general-purpose sheet, a second mode for forming an image by applying toner to a concavo-convex sheet having a concavo-convex surface, on which is formed many concavities capable of receiving toner, and a mode-switching unit for switching between a plurality of modes, wherein the plurality of modes includes the first mode and the second mode.
An image forming apparatus according to the present invention may be provided with a sheet-type detector for detecting whether a sheet is a general-purpose sheet or a concavo-convex sheet, wherein the mode-switching unit switches the image forming apparatus to the first mode when the sheet-type detector detects that the sheet is a general-purpose sheet, and wherein the mode-switching unit switches the image forming apparatus to the second mode when the sheet-type detector detects that the sheet is a concavo-convex sheet.
An image forming apparatus according to the present invention may also be provided with a sheet supply unit for receiving sheets from a removable source of sheets, and a source-type detector for detecting whether a removable source of sheets is a source of general-purpose sheets or a source of concavo-convex sheets when the removable source is in a specific location, wherein the mode-switching unit switches the image forming apparatus to the first mode when the source-type detector detects that the removable source is a source of general-purpose sheets, and wherein the mode-switching unit switches the image forming apparatus to the second mode when the source-type detector detects that the removable source is a source of concavo-convex sheets
In an image forming apparatus in accordance with the present invention, the mode-switching unit may switch to one of the plurality of modes based on the type of application outputting data to the image forming apparatus. Alternately, the mode-switching unit may switch to one of the plurality of modes based on instruction received from an application outputting data to the image forming apparatus.
In an image forming apparatus in accordance with the present invention, the mode-switching unit may switch to one of the plurality of modes based on user input.
An image forming apparatus according to the present invention may be provided with a user input device for allowing a user to select one of the plurality of modes.
An image forming apparatus according to the present invention may be provided with an electrostatic latent image carrier, a device for forming electrostatic latent image on the electrostatic latent image carrier, a developing device for developing an electrostatic latent image with toner as a toner image, a transfer device for electrostatically transferring the toner of a toner image onto a general-purpose sheet or concavo-convex sheet, and a fixing device for fixing the thus transferred toner on a general-purpose sheet in the first mode, wherein the fixing device is substantially inactive for fixing toner in the second mode.
An image forming apparatus according to the present invention may be provided with a convexity cleaner, disposed on the downstream side of the transfer device relative to the transport direction of a concavo-convex sheet, for removing toner adhered to the convexities of a concavo-convex sheet in the second mode.
An image forming apparatus according to the present invention may be provided with a mismatch indicator for providing an indication to a user when a type of sheets available to the image forming apparatus is incompatible with a mode that has been selected. The mismatch indicator may be any type of indicator, including visual and/or audible types of indicators, such as text on a display device, a lamp, an LED, a buzzer and/or an alarm of some sort.
An image forming method in accordance with the present invention comprises the steps of forming an image by applying toner onto a general-purpose sheet in a first mode, forming an image by applying toner onto a concavo-convex sheet having a concavo-convex surface on which is formed many concavities capable of receiving toner in a second mode, and switching between a plurality of modes, wherein the plurality of modes includes the first mode and the second mode.
An image forming method according to the present invention may also include the step of detecting whether a sheet is a general-purpose sheet or a concavo-convex sheet, wherein the first mode is switched to when a sheet is detected to be a general-purpose sheet, and wherein the second mode is switched to when a sheet is detected to be a concavo-convex sheet.
An image forming method according to the present invention may further include the steps of receiving sheets from a removable source of sheets and detecting whether the removable source of sheets is a source of general-purpose sheets or a source of concavo-convex sheets, wherein the first mode is switched to when the source of sheets is detected to be a source of general-purpose sheets, and wherein the second mode is switched to when the source of sheets is detected to be a source of concavo-convex sheets.
In an image forming method of the present invention, one of the plurality of modes may be switched to based on the type of application outputting data for image formation. Alternately, one of the plurality of modes may be switched to based on instruction received from an application outputting data for image formation.
In an image forming method of the present invention, one of the plurality of modes may be switched to based on user input.
An image forming method in accordance with the present invention may include the steps of activating a fixing device for fixing toner on a general-purpose sheet in the first mode and deactivating the fixing device in the second mode.
Finally, an image forming method in accordance with the present invention may include the step of removing toner from convexities on a concavo-convex sheet after image formation in the second mode.